The present invention relates to electrical penetrations which are utilized to sealingly bring electrical conductors through a nuclear containment.
A nuclear containment is the sealed shell within which radioactive material is designed to be contained in the event of a reactor vessel failure. The containment isolates the radioactivity from the outside environment. Numerous electrical conductors must be brought through the containment and effectively sealed thereto to withstand potential high temperature, radioactive exposure conditions etc.
The earliest penetration designs relied on ceramic-to-metal seals which were sealed in place through the metal shell portion of the containment. Such structures limit the flexibility of design, assembly, testing, and changes in the electrical conductor package. In the construction of a nuclear plant, it is necessary to test various components as they are completed within the containment, and to be able to charge the types of conductors being used in various penetration nozzles or apertures in which the penetration is disposed. Thus, at one stage of construction power cables are needed to be brought in via penetrations, while at other stages test as well as permanent instrumentation cables are necessarily brought through the containment.
Recent developments in penetrations have involved the use of resinous sealing material about and along the conductor in a stainless steel tubular body. The tubular body can then be mounted within a module which accommodates a plurality of such penetration devices, each of which may have several conductors sealed therethrough. A leak monitoring chamber has been provided within the penetration. Such devices are described in copending application Ser. No. 432,375, entitled "Modulator Electrical Penetration", filed Jan. 10, 1974, now U.S. Pat. No. 3,882,262 and owned by the assignee of this application.
An improved compressively sealed penetration and method of manufacture are set forth in copending application Ser. No. 471,738, entitled "Compression Sealing Penetration Elements Within A Resin Composition", filed May 20, 1974, also owned by the assignee of this application. The surface-to-volume ratios for a resinous casting to achieve an improved compressive seal between the resinous material and the conductor passing therethrough, are set forth in the aforementioned copending application.